/*

 * To change this template, choose Tools | Templates

 * and open the template in the editor.

 */

package org.apidesign.apifest08.test;

import java.math.BigDecimal;

import java.util.Currency;

import junit.framework.Assert;

import org.apidesign.apifest08.currency.Convertor;

import org.apidesign.apifest08.currency.DelegatingConvertor;

import org.apidesign.apifest08.currency.MonetaryAmount;

/**

 * A delegating convertor that checks preconditions and postconditions.

 * Useful for testing.

 * @author jdvorak

 */

public class ContractImposingDelegatingConvertor extends DelegatingConvertor {

    public ContractImposingDelegatingConvertor( final Convertor underlyingConvertor ) {

        super( underlyingConvertor );

    }

    @Override

    public ConversionResult convert( final ConversionRequest req ) {

        Assert.assertNotNull( "The request", req );

        final ConversionResult result = super.convert( req );

        Assert.assertNotNull( "Result of the convert() call", result );

        final MonetaryAmount netAmount = result.getNetAmount();

        if ( netAmount != null ) {

            Assert.assertEquals( "Converted to a different currency than specified in the request", req.getTgtCurrency(), netAmount.getCurrency() );

        }

        return result;

    }

    /**

     * Do some tests on our own.

     * @return this

     */

    public Convertor test() {

        try {

            final Currency aCurrency = Currency.getInstance( "EUR" );

            new ConversionRequest( new MonetaryAmount( BigDecimal.ONE, aCurrency ), aCurrency );

            Assert.fail( "Should have thrown an IllegalArgumentException" );

        } catch ( final IllegalArgumentException e ) {

            Assert.assertEquals( "Cannot request conversion from EUR to EUR", e.getMessage() );

        }

        return this;

    }

}